> Is the question regarding the computation of total energy per unit cell > in an infinite crystal with non-neutral unit cells? If so, then the > total energy diverges -- and so is not well-defined. (So neutralizing > backgrounds must be added in such cases to obtain meaningful results, > etc.)
Yes, this is the question and yes, of course we add a positive or negative background. We are quite confident that the resulting potential is ok, but the question is if there is a correction to the total energy due to the background charge. I believe: yes (something like Q * V-col_average / 2), but my problem is that V-coul is in an infinite crystal only known up to an arbitrary constant and thus this correction is "arbitrary". -- ----------------------------------------- Peter Blaha Inst. Materials Chemistry, TU Vienna Getreidemarkt 9, A-1060 Vienna, Austria Tel: +43-1-5880115671 Fax: +43-1-5880115698 email: pblaha at theochem.tuwien.ac.at -----------------------------------------
